Loud speaker



construed that I am limited thereto as changes in arrangement and substitution ot' equivalents may be made oy those skilled in the art Without departing from the invention as'dened in the appended claims.

What I claim is:

1. A device for converting electrical impulses into,.1so,u11d Comprising an armature arranged to lie .vilirated electrically, a sound producing diaphragm and an operatingr member therefor, said armature having a comparatively broad flat surface adapted at all points to make frictional contact with said member and to transmit lo it the .vibrations ot the armature the arrangement heilig such that the amplitude of vibrations transmitted remains the same regardless of the point of contact between said member and the broad surface ofv the armature.

2. A device of the class described coniprising` a resilient. armature and a magnet including a pair of pole pieces surrounded by''eoils located on opposite sides of said armature in juxtaposition to the free end thereof, and adapt-ed to be connected to the wires of a radio or similar apparatus so as to receive a current of varying intensity in the opposite magnets, a sound reproducing` diaphragm and an operating member therefor removably engaging said armature the latter yhaving an enlarged head for frictional engagement with said member.

A device of the class described including a double-pole permanent magnet, a resilient magnet-ie armature 'mounted in proximity to one pole of the latter, a magnetic yoke having a Winding thereon mounted in proximity to the opposite pole of said pernnanent magnet, the ends of said magnetic yoke being located at opposite sides jot said armature in juxtaposition to the free end thereof. said armature having a lat surface on its free end in a plane perpendicular to its length and arranged totransmit movements of the armature, to a sound producing diaphragm'by mere frictional contact with said flat surface.

In Witness whereof, I have hereunto signed my name.

. ROBERT IV. ERICKSON. 

